Personal emergency response (PER) systems are known in the art. Representative examples of such systems are disclosed in U.S. Pat. Nos. 4,656,319, 4,524,243, 4,064,368 and 3,989,900, owned by the assignee of the present application. A PER system includes a central station and one or more remote subscriber stations such as a residence or business interconnected therewith.
The central station may be any facility such as a hospital, a police station, a fire station, a phone answering service or a burglary alarm monitoring service which responds to alarm messages generated by remote subscriber stations to provide assistance thereto. The central station is interconnected with the remote subscriber stations via communications links.
Various communication links may be utilized to interconnect the central station with remote subscriber stations including telephone communication lines, cable television transmission lines, radio frequency transmissions or dedicated land lines. Typically, telephone communication lines are utilized due to the prevalence of in-place telephone networks and the minimal expense necessary to interface a personal emergency response system with a telephone network.
Each remote subscriber station includes a subscriber unit interfaced with the communications link. Upon activation of the subscriber unit in response to a predetermined event, an alarm message is transmitted via the communications link to the central station.
Various means may be utilized to activate the subscriber unit to transmit an alarm message. The subscriber unit may include a timing/logic circuit which is operative to automatically activate the unit upon expiration of a predetermined period of time. A subscriber unit of this type will also include a subscriber-activated reset means which reinitializes the timing circuit. The reset means may be interfaced with any device frequently used by the subscriber such as electrical switches, television sets, radios, refrigerators, stoves or telephones wherein the use of any such device causes the timing circuit to be reset to zero.
The subscriber unit may also be activated by means of a portable help button carried by the subscriber. A portable help button is particularly useful to elderly or infirm subscribers who may be prone to acute emergencies requiring an immediate response. The portable help button also has utility for notifying the central station of an event such as a fire or an intruder in the remote subscriber station. When immediate assistance is required by the subscriber, the portable help button is manually operated to activate the PER system.
The portable help button is typically a wireless unit which transmits a coded or uncoded signal to activate the subscriber unit located within the remote subscriber station. Most commonly the portable help button is a radio transmitter, although infrared and ultrasonic transmitters may also be used.
Since the portable help button is a critical link of the PER system, it is of paramount importance that the portable help button be periodically tested to ensure proper operation thereof in combination with elements of the subscriber unit and/or to inform the subscriber of any limiting conditions. Since the portable help button is self powered, one possible deficiency is the depletion of the power source to such a level that the portable help button is no longer capable of generating a signal which will activate the PER system. Other possible deficiencies of which the subscriber should immediately be made aware of include any help button malfunction or damage which precludes generation of the activating signal.
Furthermore, for PER systems which utilize a coded activating signal, it is desirable to ensure that the portable help button is transmitting a properly coded activating signal and to ensure that the subscriber unit is synchronized to receive and recognize the coded activating signal broadcast by the corresponding portable help button.
In addition to deficiencies affecting the functioning of the portable help button and/or the subscriber unit, it will be appreciated that a wireless portable help button may also be subject to range limitations and/or transmission dead spots, that is, locations in the vicinity of the subscriber station from which an activating signal cannot be received by the subscriber unit.
It is therefore of paramount importance that the subscriber be made aware of any functional, range and/or location deficiencies affecting the portable help button. While it is desirous to periodically test the operation of the portable help button, it will be appreciated that such testing should not cause the PER system to generate and transmit an alarm message to the central station. Transmission of an alarm message to the external central station during testing unnecessarily ties up the resources of the central station which may result in delayed responses to actual emergency conditions in other remote subscriber stations as well as provoking an unnecessary response to the particular remote subscriber station.